As it is known, boxing machines are designed for boxing articles or packs of articles of different kind (that is, more commonly, for packaging articles into box-like containers); in general and qualitative terms, the operations, that follow one another in similar machines include: picking up a flat folded tubular blank from a containing magazine, erecting the blank, so that it assumes a parallelepiped shape of rectangular section and vertical (horizontal) axis, introduction of articles or packs of articles into the erected blank, in vertical (horizontal) direction, folding the blank flaps and their mutual sealing, so as to define the bottom and a cover of a corresponding box of articles. It is understood that some of these operations can be performed in a different order than the cited one, or include more phases (for example, it is possible that first the flaps forming the box bottom are folded, then the articles are introduced into the erected blank and next, the flaps defining the box cover are folded), according to the type of the machine.
It is known in the boxing machines, that cross-section of the box to be obtained is rectangular, and in some cases even square.
In the last case, it occurs in the feeding station magazine that the diagonally opposite pre-creasing lines in flat configuration, situated at the blank center, are exactly one over another, unlike in the rectangular section case, in which they are shifted.
For this reason, the blanks are less resistant to bending, therefore the ones placed in the lower part of the stack can lose the planarity and assume a curved downward conformation, due to the weight resting on them.
These drawbacks are amplified by increasing dimensions, and consequently weight, of the blanks.
In boxing machines of known type, which include the introduction of articles in vertical direction, the square blank is usually taken to the filling station by conveying means, which are aimed at maintaining, no matter of how the size changes, the bottom and the longitudinal medium line in alignment with two corresponding stationary planes, one horizontal and the other vertical. In this way, manipulating means, aimed at introducing the articles into the boxes being formed and working in a position corresponding to the filling station, perform vertical strokes having constant maximum width, independently from the dimensions of the containers being used. Consequently, a production rate, which can be accepted for boxes of large dimensions, does not imply satisfying filling times for boxes of minimum dimensions, or anyway smaller, for which a higher production rate is normally expected.